1. Field of the Invention
The present invention relates to a new and improved method of encapsulating temperature sensitive electronic devices in a wax-like material having a high coefficient of fusion so as to provide a heat sink for protecting the temperature sensitive electronic devices against intense heat. Solid state memory devices are commonly used in aircraft for storing data and protective enclosures are provided for these devices which are designed to survive aircraft accidents, crashes, fires, etc. in order to preserve the stored data so that accident investigators may have a useful bank of information available to determine the cause of the aircraft accident or crash.
In the context of this disclosure, a "solid state memory" or "a solid state memory module" may comprise a total assembled "end product" commonly termed in military nomenclature as a CSMU standing for Crash Survivable Memory Unit. Individual "chips" in these memories comprise "memory devices" such as an EEPROM, "flash" memory and other types of devices. Chips are usually mounted on PC boards (printed circuit boards), encapsulated in wax, and surrounded by a fiberglass (or other) container, with a flex-print cable connected thereto and the assembly is referred to as a "wax filled memory module" (WFMM).
2. Description of Pertinent Art
U.S. Pat. No. 4,694,119 discloses a solid state memory contained in a small crash protective container including a device encapsulating, heat sink formed of synthetic amide wax designed to protect electrically erasable programmable read only memory (EEPROM or other solid state) devices from damage due to heat and fire.
U.S. Pat. No. 4,944,401, issued Jul. 31, 1990, for a CRASH SURVIVABLE ENCLOSURE FOR FLIGHT RECORDER discloses a solid state memory device carried in a crash survivable flight data recorder system containing an organic wax or wax-like material of a type known as HM 23 or ACRAWAX, manufactured by GLYCO, INC. of Greenwich, Conn., and having a relatively high heat of fusion so as to provide a heat sink for the protection of the solid state memory device and circuit board that is contained in a crash protected enclosure.
The present invention is directed toward a new and improved method for encapsulating electronic devices of the character described in a synthetic wax or wax-like material or similar substance having a relatively high heat of fusion to provide a heat sink for absorbing heat for the protection of the memory devices against high temperature and fire commonly encountered in aircraft crashes.